Participants navigate the Combat Center Bike Trail during the annual Earth Day Bike ride held aboard Marine Corps Air Ground Combat Center, Twentynine Palms, Calif., April 8, 2017. The 11-mile ride started at Range 100. (U.S. Marine Corps photo by Lance Cpl. Dave Flores) - Participants navigate the Combat Center Bike Trail during the annual Earth Day Bike ride held aboard Marine Corps Air Ground Combat Center, Twentynine Palms, Calif., April 8, 2017. The 11-mile ride started at Range 100. (U.S. Marine Corps photo by Lance Cpl. Dave Flores)